The oxygen distribution circuit for the cockpit crew supplies oxygen to the cockpit of the aircraft in the event of the cabin pressure falling below a critical value. In modern aircrafts, the oxygen distribution circuit for the cockpit crew is separate from the oxygen distribution circuit for the passengers of the aircraft. Typically, the oxygen distribution circuit for the passengers includes a chemical source of oxygen, that is to say, upon the cabin pressure falling below the critical value, a chemical reaction is initiated as a result of which oxygen is created. Conversely, the cockpit oxygen distribution circuit uses oxygen bottles from which oxygen is supplied to the cockpit of to the aircraft in an emergency situation.
FIG. 1 shows an example of a cockpit crew oxygen distribution circuit. An oxygen bottle 10 is provided as the oxygen source. The oxygen bottle 10 is connected via conduits 5, 15 to masks 4 for the cockpit crew. These masks 4 are normally stored in storage boxes 3 from which they are released upon pressure drop inside the cockpit. A pressure gauge 20 is provided in the outlet of the oxygen bottle 10. Reference numeral 30 indicates a pressure regulator which regulates (reduces) the pressure of the gas provided by the oxygen bottle 10. An electromagnetic valve 40 is provided in order to start or terminate oxygen flow from the oxygen bottle 10. During normal operation of the aircraft, the electromagnetic valve 40 is normally open and can be closed by the cockpit crew via a switch provided inside the cockpit of the aircraft (see e.g. switch 44 in FIG. 4). Furthermore, a pressure switch 50 is provided in conduit 15. When the gas pressure inside conduit 15 drops below a predetermined value, the pressure switch 50 opens, thereby initiating a low pressure signal on a display inside the cockpit for alerting the cockpit crew that the gas pressure inside conduit 15 is no longer sufficient for providing the cockpit crew, in an emergency situation, with a sufficient amount of oxygen. It goes without saying that in an actual aircraft, a plurality of these oxygen bottles 10 are provided and that conduit 15 branches off towards these oxygen bottles 10. Conduit 13 is provided for discharging an overpressure overboard the aircraft.
The ground tests of an aircraft require a number of different tests to be conducted. These tests include testing, for example, the pressure gauge 20, the pressure regulator 30, the electromagnetic valve 40 and the pressure switch 50 with regard to correct connection of these components to the cockpit oxygen distribution circuit, that is to say whether these components are correctly connected to the signal lines leading to control means inside the cockpit. Moreover, it is important to check whether these components can be controlled as specified, and that, for example, the correct pressure that can be provided by the cockpit oxygen distribution circuit to the cockpit of the aircraft is displayed correctly on a display inside the cockpit.
It is therefore an object of the invention to provide a tester for testing operational reliability of a cockpit oxygen distribution circuit with which the electrical connection and the control of the various components of the cockpit oxygen distribution circuit can be tested for operational reliability.